In boats or vessels of the larger type, in the range of seventy(70) feet to one-hundred-fifty (150) feet, the engine room is located a fair distance from the wheel house and the electrical requirements are relatively high. In such vessels, typically two or more generators are used to supply the electrical power for the vessel. Each generator is located in the engine room and each is connected to a prime mover or engine, typically an engine for each generator. The electrical load of the vessel is distributed between the two generators depending on power requirements. If the loading is not high, only one generator may be used and, of course, when the vessel is at shore and shore power is available, neither generator need be used and the electrical load of the vessel will be supplied by shore power coupled directly to service the load.
Typically, a manual type load control has been used. This technique comprises transfer switches and control breakers located in the engine room separate from the wheel house. In order to properly distribute the load to the generators, the transfer switches were manually operated to connect the load to the generators in an appropriate fashion. The operation of the generator would be initiated in the wheel house by a first operator. Once the generator was operating, it was necessary to manually operate the transfer switches in the engine room to transfer the load to the generator. Subsequently, if additional power was necessary, the same procedure was used; that is, the operation of a second generator was initiated from the wheel house and, thereafter, the second generator was connected to the load again by manually operating a second transfer switch. This is time consuming and inconvenient.
If it is desired to control the electrical loading and generator operation from the wheel house rather than the engine room, it is possible to locate the transfer switches in the wheel house. However, such a location for the transfer switches mandates a large cable running from the wheel house to the engine room where the generators are located. This is costly, unsightly and the cable is obtrusive. Further, the transfer switches still must be manually operated.
In such prior art systems, circuit breakers must be used to prevent overload on the generators. The circuit breakers are controlled by electrical contactors. Electrical contactors are similar in operation to solenoids wherein a coil is used to create a magnetic field which brings two conductive members into or out of contact with each other and which thereby allows power to flow or be interrupted. The use of such contactors, however, is a problem in many applications where a coil may fail. If the contactor opens, power will be interrupted between the load and the generator. If the power to the load is interrupted because of such malfunction, it is difficult to remedy the difficulty without replacing the contactor which may be inconvenient to do while away from shore. The contacts of the electrical contactor may be physically forced together to allow power to flow but the potential for damage to the generator and for safety problems is clear. Further, the necessity for a circuit breaker in addition to the contactor is required.